This invention relates to a milk-containing acid syrup and a method for the production of the same.
In the conversion of milk into an acidified milk by fermentation or by addition of an acid, casein contained in the milk coagulates in the form of coarse particles as the milk surpasses its isoelectric point, and the coarse particles are liable to precipitate in accordance with Stokes' law because these particles are hydrophobic. In the circumstances, various studies have been continued to produce an acidified milk beverage in which the casein is stably dispersed over a long period.
The phenomenon of precipitation of coarse casein particles mentioned above becomes conspicuous as the casein content increases, so the milk-containing acid beverages which are actually available in the market are limited to the so-called straight drinks (ready-to-drink) having a lowered casein content (about 0.3 w/w% in the acidified milk contemplated by this invention) and syrups of a higher casein content (about 2.4 w/w% in the acidified milk contemplated by this invention) which contain therein more than 50 w/w% of sugar so as to increase the viscosity and specific gravity of their liquid portion.
The above mentioned syrups containing a higher casein content are drunk by diluting with water or carbonated water to about 5 times the original volume.
In the case of a syrup containing more than 50 w/w% of sugar, there is a problem of excessive caloric intake which has been causing increased public concern. Especially when the sugar content is disproportionately high as compared with good body of the acidified milk, the consumer diluting the syrup tends to rely on the degree of sweetness as a criterion for dilution and, consequently, takes more sugar than is normally required. The use of sugar in a large amount also entails the problem of high price of sugar. In these circumstances, there has been felt the need for lowering the sugar content of such a syrup without impairing the stable dispersion of casein (without lowering the casein content). The inventors have made studies on a method of the production of a syrup which has an excellent stability of dispersed casein even when its sugar content is lowered. They have consequently achieved the object by incorporating a novel idea into the conventional technique and further providing a method for the production of a stable syrup which permits its casein content and sugar content to be varied in greater ranges than those attainable in the conventional syrups. Thus, the method of the present invention provides not merely syrups which, like the conventional countertypes, are drunk after dilution to about 5 times the original volume but also syrups being diluted to from about 2 to about 6 times the original volume.